Cubic Boron Nitride (CBN) is a superabrasive that is second in hardness only to diamond. It offers greater abrasion resistance and thermal conductivity than conventional abrasives like silicon carbide and aluminum oxide, making it the preferred abrasive in many advanced industrial grinding applications. Now you can combine the advantages of this fast-cutting abrasive with the convenience and ease of use of Spydercos Tri-Angle Sharpmaker with these CBN-coated Sharpmaker rods.Sold as a pair. 7 X 0.5 (178mm X 13mm)